Hostile unmanned aerial vehicles and precision guided munitions (PGMs) frequently use satellite signals to navigate to a designated target. Such PGMs can include, for example, guided mortars, guided artillery projectiles, unmanned aerial vehicles (UAVs), missiles, glide bombs, and other projectiles capable of acquiring and using global positioning systems (GPS) or other SATNAV signals for guidance. A typical SATNAV PGM guidance system receives satellite signals to guide itself to a designated target. The satellite signals can be based on GPS technology or SATNAV alternatives to GPS, such as GLONASS, Galileo, or Beidou for example.
Current countermeasures against incoming objects use projectiles, such as bullets, that are configured to destroy or to disrupt the trajectory of an incoming projectile. The problems with countering a projectile with a counter-projectile, however, are numerous including the possibility of inadvertently striking a friendly aircraft or civilian buildings, reloading issues, shrapnel, and the possibility of misfiring.
Another countermeasure option involves the use of a targeted electromagnetic beam to heat a projectile to a disruption temperature to deflagrate the projectile. This solution, however, also risks potential problems with inadvertently damaging civilian aircraft or infrastructure and issues involving the energy or chemicals such a system would require.
Another countermeasure option, for missiles or weapons targeting vehicles in motion, is described in U.S. Pat. No. 7,489,264. That option contemplates using multiple electronic signals to coordinate electronic jamming signals for protecting multiple vehicles physically separated from one another against Home-on-Jam weapons. The vehicles exchange messages and coordinate a system to emit an alternate jamming signal creating a false target. The '264 system, however, does not contemplate a satellite guided projectile or a fixed-position defense.
Another countermeasure option, for SATNAV broadly, is to disrupt or eliminate satellite communication for all area-wide guidance systems at the satellite's transmission. This elimination, jamming, or spoofing of all satellite communication, however, would also disrupt all nearby equipment that also relies on SATNAV signals to operate, including UAVs, communication systems, and hand-held GPS navigation devices. The consequences of persistently jamming or spoofing all SATNAV signals in order to disrupt an incoming PGM attack would severely disrupt broad military and civilian activities. Additionally, there might be serious diplomatic consequences for disrupting the SATNAV signals of a system belonging to another state or, for example, on an expeditionary force disrupting the use of civilian GPS signals in a foreign city.
Hence, it is known to coordinate the transmission of jamming signals from a plurality of cooperating vehicles, and to shut down all STANAV guidance systems through disruption of satellite transmissions. However, there is yet no technical solution for targeted defending of a fixed position or base against incoming projectile(s) through disruption of localized satellite signals guiding the projectile(s).